Usually I don't much bother about scratches, but this one was deep and I did not want water getting into the wood, so I got on to it right away.

Years back I got a deep scratch on one of my boats. It penetrated the glass down to the cedar, below the waterline. For the science of it I left alone for 2 years and used the boat a lot.

After that time I sanded away the glass around it let it dry and did a repair like your. There was a small area of minor discoloration surrounding the area due to water penetration (less than maybe 1/4 inch larger than the initial damage), but it didn't rot, delaminate or fall apart.

My conclusion is that while best practice is to fix this kind of damage as soon as possible, if you don't have the time right away, it can go a long time without a fix.